Fox News Channel star Megyn Kelly is bright, beautiful and blunt when she needs to be. Just ask Karl Rove.

Her willingness to take on all-comers, even conservative hero Rove — as she famously did on election night last November — is one reason Fox News Chairman Roger Ailes has promoted Kelly to a plum prime-time perch. On Monday, the network's 17th anniversary, "The Kelly File" premieres between the opinion-heavy programs of the network's conservative firebrands Bill O'Reilly and Sean Hannity.

But there's one thing Kelly insists she won't be: "I'm not going to be the female Bill."

Kelly doesn't intend the show to be a megaphone for her opinions, even though she's got plenty. Instead, the anchorwoman, in a phone interview last week, said she wants to produce a fast-paced, razor-sharp recap of the news of the day.

She plans to keep her own politics out of it.

"I'm a news anchor, I'm not an ideologue," Kelly said. "I don't want to be an opinion anchor."

For that reason, the 42-year-old former trial lawyer from the true-blue state of New York doesn't quite fit the Fox News mold. "The Daily Show's" Jon Stewart once called Kelly his "favorite person over there" at Fox News.

Republicans have congratulated her for revealing conservative stripes, while some on the left believe she might be a closet liberal. To both camps, "I always say to them: You assume too much," she said. "Nobody really knows my true feelings on a lot of issues."

This much is certain: Kelly pledges her allegiance to Ailes, who is embarking on a mid-course adjustment to Fox News' hugely successful formula.

Last year, the network generated $1.9 billion in revenue, according to consulting firm SNL Kagan. Its annual profit topped $1 billion. This year, it's drawn an average of 1.8 million nightly prime-time viewers, nearly three times more than MSNBC or CNN, according to Nielsen.

But for all its success, Fox News is grappling with an age issue. The median age of its audience is over 65, which is less appealing to advertisers. Although Fox News has a commanding lead among the important demographic of viewers aged 25 to 54, it wants to make a move now to protect its advantage.

The challenge is to attract younger viewers without alienating older O'Reilly and Hannity viewers.

"The Kelly File" represents only the fifth prime-time change that Ailes has made in Fox News' history. During that same period, his competitors CNN and MSNBC have made more than 70 shifts in a futile effort to catch the No. 1 cable news network.

"This is the biggest prime-time shake-up ever at Fox News," said Eric Boehlert, senior fellow for the liberal watchdog group Media Matters for America. "But the question is: Will this shift change the political tone of Fox News? Megyn Kelly is obviously more pragmatic than Sean Hannity. Is she going to be the centrist prime-time host? Moderation is not what drives Fox programming."

"Megyn is the whole package," said Bill Shine, Fox News executive vice president of programming. "She is very strong and nice — and unpredictable. If people try to cross her or try to get some B.S. past her, she will call them out. It doesn't matter if they are on the left or on the right."

Republican strategist Rove discovered that on election night when he attempted to put the brakes on early calls that President Obama was cruising toward victory. Not enough votes had been counted in key Republican precincts, he said, votes that could put Mitt Romney ahead.

"Is this just math that you do as a Republican to make yourself feel better, or is it real?" Kelly asked Rove before a record audience of nearly 12 million people watching Fox News.

An hour later, the atmosphere grew tense as the Ohio returns were rolling in. Fox News declared Obama the winner of the election. Again, Rove protested.

"Well, that's awkward," Kelly said.

To settle the dispute came the walk watched round the world. With microphone in hand and cameras trained on her every step, Kelly made her way to the "Decision Desk" data room for a live interview with vote-count analysts. The Fox team had practiced the walk, thinking they might have to use it to fill time if the race was too close to call, but they didn't expect to use it to stifle an on-air commentator.

"That was a real question, it wasn't me trying to needle Karl," Kelly said. "It was something I thought our Republican viewers at home would want to know: Is this real, or are you just giving me a soothing balm? And in another hour or so the hammer is going to come down?"